A method of heat treatment of a non-metallic or metallic item is provided. The method includes at least one step A) of heat transfer between the item and a heat transfer fluid A′ including a fluid medium and nanoparticles. The heat transfer fluid has a heat transfer coefficient above the heat transfer coefficient of water. The method also includes at least one step B) of heat transfer between the item and a heat transfer fluid B′ including a fluid medium and nanoparticles. The heat transfer fluid B′ has a heat transfer coefficient different from the heat transfer coefficient of A′ and above the heat transfer coefficient of water. The heat transfer fluids A′ and B′ are different.

A method for heat treating a horological component includes the following steps: heating of the component by irradiation, using a laser beam, of at least 80% or at least 90% of the projected surface of the component parallel to the direction of the laser beam, and cooling of the component in a gas stream.

A method for heat treating a horological component includes the following steps: heating of the component by irradiation, using a laser beam, of at least 80% or at least 90% of the projected surface of the component parallel to the direction of the laser beam, and cooling of the component in a gas stream.

A method of heat treatment of a non-metallic or metallic item is provided. The method includes at least one step of heat transfer between the item and a heat transfer fluid A′. The heat transfer fluid A′ includes a fluid medium and nanoparticles having a lateral size between 26 and 50 μm. The heat transfer fluid has a heat transfer coefficient below the heat transfer coefficient of water.

A method of heat treatment of a non-metallic or metallic item is provided. The method includes at least one step of heat transfer between the item and a heat transfer fluid A′. The heat transfer fluid A′ includes a fluid medium and nanoparticles having a lateral size between 26 and 50 μm. The heat transfer fluid has a heat transfer coefficient below the heat transfer coefficient of water.

A seamless steel pipe heat-treatment-finishing-treatment continuous facility includes: a heat treatment apparatus; a steel pipe inspection apparatus which performs a test for a surface defect and/or an inner defect of the seamless steel pipe, the steel pipe inspection apparatus being disposed downstream of the heat treatment apparatus; a main transfer mechanism which forms a main transfer path MT for transferring the seamless steel pipe, discharged from the heat treatment apparatus, to the steel pipe inspection apparatus disposed downstream of the heat treatment apparatus; and a first forced steel pipe-temperature reduction apparatus which forcibly reduces a temperature of the seamless steel pipe on the main transfer path MT, the first forced steel pipe-temperature reduction apparatus being disposed on the main transfer path MT at a position downstream of the heat treatment apparatus and upstream of the steel pipe inspection apparatus.

A thick steel plate for high heat input welding and having great heat-affected area toughness and a manufacturing method therefor, comprising the steps of smelting, casting, rolling, and cooling. Chemical composition is properly controlled for the steel plate and satisfies 1Ti/N6 and Mg/Ti>0.017, where effective S content in steel=S1.3 Mg0.8 Ca0.34 REM0.35 Zr, and effective S content in steel: 0.0003-0.003%; finely dispersed inclusions may be formed in the steel plate, and the amount of composite inclusion MgO+Ti.sub.2O.sub.3+MnS in the steel plate is controlled at a proportion greater than or equal to 5%. The tensile strength of a base material so acquired is 510 MPa, insofar as welding input energy is 200-400 kJ/cm, the average Charpy impact work of the steel plate at 40 C. is 100 J or more, at the same time, the average Charpy aging impact work of the base material of thickness at 40 C. is 46 J or more.

A thick steel plate for high heat input welding and having great heat-affected area toughness and a manufacturing method therefor, comprising the steps of smelting, casting, rolling, and cooling. Chemical composition is properly controlled for the steel plate and satisfies 1Ti/N6 and Mg/Ti>0.017, where effective S content in steel=S1.3 Mg0.8 Ca0.34 REM0.35 Zr, and effective S content in steel: 0.0003-0.003%; finely dispersed inclusions may be formed in the steel plate, and the amount of composite inclusion MgO+Ti.sub.2O.sub.3+MnS in the steel plate is controlled at a proportion greater than or equal to 5%. The tensile strength of a base material so acquired is 510 MPa, insofar as welding input energy is 200-400 kJ/cm, the average Charpy impact work of the steel plate at 40 C. is 100 J or more, at the same time, the average Charpy aging impact work of the base material of thickness at 40 C. is 46 J or more.

A method for producing a hot-dip galvanized steel sheet includes supplying humidified gas to the soaking zone 12 in a manner such that: in passes in which the steel sheet moves upward, the humidified gas is supplied from first humidified gas supply ports 40A to 40E provided at positions higher by 1.0 m or more and 5.0 m or less than the centers of lower hearth rolls 54 and overlapping the steel sheet in the passes when viewed from the side of the soaking zone; and in passes in which the steel sheet moves downward, the humidified gas is supplied from second humidified gas supply ports 42A to 42E provided at positions lower by 1.0 m or more and 5.0 m or less than the centers of the upper hearth rolls 52 and overlapping the steel sheet in the passes when viewed from the side of the soaking zone.

A method of heat transfer between a metallic or non-metallic item and a heat transfer fluid is provided. The method includes a fluid medium and nanoparticles. A thickness/lateral size ratio of the nanoparticles is below 0.00044. The nanoparticles do not include carbon nanotubes.